Element mounting means for straight bar knitting machines



Aug. 15, 1961 J. D. WENRICH ELEMENT MOUNTING MEANS FOR STRAIGHT BAR KNITTING MACHINES Filed Dec. 10, 1959 Fig. 1.

INVENTOR. BY John 0. Wenr/c/v fl/x/ United States Patent 2,995,911 ELEMENT MOUNTING MEANS FOR STRAIGHT BAR KNITTING MACHINES John D. Wenrich, Fleetwood, Pa., assignor to Textile Machine Works, Wyomissing, Pa., a corporation of Pennsylvania Filed Dec. 10, 1959, Ser.No. 858,714 6Claims. (Cl. 66114) This invention relates to warp knitting machines and more particularly to the needle bar assembly of such macln'nes which is constructed in a manner to maintain the operating relation of the needles mounted in the bar assembly with other cooperating parts of the machine.

In warp knitting and like machines which are operated at high speeds, the steel bars in which the knitting and yarn feeding elements are mounted are from seven to fourteen feet or more in length and are constructed of materials that must provide sufiicient rigidity to maintain correct operating relationships between the elements. During operation of such machines, suflicient heat is generated by the operating parts to cause an increase in the temperature of the bars which is considerably above the normal temperature of the room in which the machine is operated. This increase in temperature in the bars for the elements heretofore caused a linear expansion of the bars and consequently linear movements of the elements which very often resulted in misalignment of the elements and damage thereto.

Heretofore, in order to overcome the misalignment of the various elements caused by linear expansion, the bar assemblies for the elements were constructed of a material having a low coefiicient of linear expansion such as Invar which is an alloy of steel with a high percentage of nickel. While the substitution of invar for prior materials having a higher coefiicient of heat expansion solved the problem of misalignment in the elements, the greater weight of the bar assemblies and particularly the bar assembly for the needles posed the additional problem in that more power was required to perform the greater work load at the high speeds at which the machine is operated. In attempts to reduce the work load and at the same time retain the advantages obtained through the use of the lower expanding materials, the needle bar was made of invar and the clamps for holding the needles in position on the bar were made of aluminum or other similar lightweight material. However, although this use of such lightweight material in the clamps did result in some weight advantage, the greater linear expansion in the individual clamp elements which must be placed in closely adjoining relationship caused them to jam against each other making it difficult to remove and replace the clamp elements when replacing damaged needles.

It is therefore an object of the instant invention to provide means for overcoming the above mentioned and other difficulties occurring in high speed warp knitting and like fabricating machines having long supporting bars for the needles and other elements constituting the fabricating means of the machine.

Another object of the invention is to provide bar assemblies for the fabricating elements of a warp knitting machine, the primary parts of the assemblies being constructed of materials having a low coefiicient of linear expansion and other parts being constructed of lightweight material having a higher coetiicient of linear expansion which acts to reduce the over-all weight of the bar assembly without aflecting the accuracy of alignment between the fabircating elements obtained by the use of the lower expanding material.

With these and other objects in view which will become apparent from the following detailed description of the illustrative embodiment of the invention shown in the accompanying drawing, the invention resides in the novel elements, features of construction and cooperation of parts, as hereinafter more particularly pointed out in the claims.

In the drawings:

FIGURE 1 is an elevational view of a needle bar assembly according to the invention of warp and other like straight bar knitting machines;

FIG. 2 is an enlarged detailed view of a portion of the needle bar shown within the dot-and-dash outline A of FIG. 1; and

FIG. 3 is a cross-sectional view taken along the line 23-4: of FIG. 2.

Referring to the drawing and more particularly to FIGS. 1 and 2 thereof, there is shown a needle bar assembly 10 for a Warp or tricot knitting machine comprising a bar 11 extending the full length of the assembly (FIG. 1), a bed element 12 which is secured to one face of the bar by screws 15 and a bed member 16 which is secured by screws 17 in a groove 20 extending lengthwise of the bar (FIG. 3). The bed element 12 is provided with spaced transversely extending slots 21 for needles 22 and the bed member 16 is provided with apertures 25 which are aligned with the slots to receive butt portion 26 of the needles. The needles 22 are maintained in the grooves 21 and apertures 25 by sectional clamp members 27 whichare secured on the bar 11 in substantially abutting relation by screws 30.

In order to substantially eliminate linear expansion in the needle bar assembly which is caused by an increase in the temperature of the bar during operation of the machine and which causes misalignment of the needles with respect to the other loop forming elements of the machine, and at the same time provide sufficient rigidity in the bar assembly to maintain accurate relation with other operating parts of the machine it was the practice heretofore to form the bar 11, bed element 12 and clamp members 27 of an alloy steel such as Invar which is approximately thirty-six percent nickel and has a coefficient'of linear expansion of only one-seventh that of steel. It was found, however, that while the use of Invar did correct the expansion problems, the increased weight of the bar assembly due to the use of the Invar material greatly reduced the operating efficiency of the machine.

Heretofore, in order to reduce the weight of the needle bar assembly without sacrificing the advantages obtained by the use of the Invar material, the bar 11 and bed element 12 were constructed of Invar and the clamp members, which constitute approximately one-third of the mass of the bar assembly, were constructed of aluminum or other lightweight metals such as magnesium such materials however having a higher coefiicient of linear expansion than steel. However, while the lighter weight material of the clamp members considerably reduced the weight of the bar assembly 10, the greater expanding movements in the clamp members resulting from the increase in temperature during operation of the machine both in relation to each other and in relation to the bar 11 and bed element 12, caused the clamp members to jam against each other making it necessary to remove several adjacent clamps in order to replace a broken needle beneath one of them.

In accordance with the instant invention, in order to retain the advantages obtained by both the low expanding quality of the Invar and the lightweight material of the clamp members 27 each clamp member is provided with a strip 31 which is secured to the clamp member by adhesive or the like for engagement with the needles 22. The strips 31 are preferably constructed of Invar and are of such dimensions as not to materially increase the weight of the clamp members 27. position on the bar 1 1, the ends of the adjacent strips 31 are insubstantially abutting relationship (FIGS. 1 and 2) and this relationship will remain constant during temperature variations inasmuch as for any linear movement which may occur in the individual Strips 3 1 there will be a corresponding linear movement in the adjacent portions of the bar 1 1 and bed element 12. The ends of the clamp members 27, on the other hand are spaced from each other which permits the individual clamp members 27 to expand linearly relative to the strip members 31 without affecting the position of the strips and relative to each other without causing engagement therebetween.

While the metal Invar is referred to herein, it is to be understood that any metal having the same or similar characteristics may be employed in constructing the bars and clamps, as above set forth, that will effectively limit or eliminate the detrimental effects caused by linear expansion in the parts. .Further, while the material of the clamp members is referred to as aluminum, the clamp members may be constructed of any lightweight metal or other material that will materially reduce the over-all weight of the needle bar assembly.

Of course, the improvements specifically shown and described by which the above results are obtained, can be changed and modified in various ways without departing from the invention herein disclosed and hereinafter claimed.

I claim:

1. A bar assembly for fabricating elements of a straight bar knitting machine including a main bar portion constructed of an alloy steel having a low coefficient of linear expansion, a bed element for supporting said fabricating elements in spaced alignment on said main bar portion, and clamp members for holding said fabricating elements in said bed element, each of said clamp members having a portion constructed of a lightweight metal having a higher coefiicient of linear expansion than the alloy steel of said main bar portion and a portion of alloy steel having the same coefficient of linear expansion as said alloy steel of said main bar portion, the ends of said lightweight metal pontions of said clamp members being spaced from each other.

2. A bar assembly for fabricating elements of a Warp knitting machine, including a main bar portion of an alloy steel having a low coefficient of linear expansion, a bed element on said main bar portion for supporting said fabricating elements in spaced alignment on said bar portion, and sectional clamp members for holding said fabricating elements in said bed element, each of said clamp elements having a portion constructed of alloy steel having the same coefiicient of linear expansion as said main bar portion for engagement with said fabricating elements, and a portion of lightweight metal having a higher coefiicient of linear expansion than the alloy steel portion of said clamp member, the ends of said lightweight metal portions of said clamp members being spaced from each other.

3. A bar assembly for fabricating elements of a warp knitting machine including a main bar portion constructed When in assembled '4 of an alloy steel having a low coefiicient of linear expansion, a bed element having slots for receiving said fabricating elements and being constructed of the same alloy steel as said main bar portion, and sectional clamp members for holding said fabricating elements in the slots in said bed element, said clamp members having a main portion of lightweight metal having a higher coeificient of linear expansion than said alloy steel, and a strip of the same alloy steel as said bed member for engagement with said fabricating elements, the ends of said main portions of said clamp members being spaced from each other.

4. A bar assembly for fabricating elements of a warp knitting machine, including a main bar portion of alloy steel having a high percentage of nickel, a bed element on said main bar portion having slots for receiving said fabricating elements and being constructed of the same alloy steel as said main bar portion, and sectional clamp members for holding said fabricating elements in the slots in said bed elements, said clamp members having a main portion of aluminum and a strip of the same alloy steel as said main bar portion for engagement with said fabricating elements, the ends of said main portions of said clamp members being spaced from each other.

5. A bar assembly for fabricating elements of a warp knitting machine including a main bar portion of an alloy steel having a high percentage of nickel, a bed element on said main bar portion having slots for receiving said fab ricating elements and being constructed of the same alloy steel as said main bar portion, and sectional clamp members for holding said fabricating elements in the slots in said bed elements, said clamp members having a main portion of magnesium and a strip of the same alloy steel as said main bar portion for engagement with said fabricating elements, the ends of said main portions of said clamp members being spaced from each other.

6. A bar assembly for fabricating elements of a straight bar knitting machine including a main bar portion constructed of an alloy steel having a low coefficient of linear expansion, a bed element having slots for receiving said fabricating elements and being constructed of the same alloy steel as said main bar portion, and sectional clamp members for holding said fabricating elements in the slots in said bed element, said clamp members having a main portion of lightweight metal having a higher coetficient of linear expansion than said alloy steel and a strip constructed of the same alloy steel as said bed member for engagement with said fabricating elements, the ends of said main portions of said clamp members being spaced from each other to thereby prevent engagement of said main portions during linear expansion thereof and the ends of said strips being substantially in abutting relation.

References Cited in the file of this patent UNITED STATES PATENTS 2,005,674 Gastrich June 18, 1935 2,254,201 Anderson Sept. 2, 1941 2,653,906 Bitzer Sept. 29, 1953 2,854,835 Bitzer Oct. 7, 1958 2,902,847 Kohl l Sept. 8, 1959 

